Method for determining procainamide levels in blood or urine

ABSTRACT

A qualitative and quantitative determination of procainamide blood levels may be obtained by contacting a sample of urine or denatured blood with dimethylcinnamaldehyde in the presence of an acid and comparing the resulting characteristic color with a reference standard.

United States Patent Parekh 5] Feb. 13, 1973 4] METHOD FOR DETERMINING [56] References Cited PROC-AINAIVIIDE LEVELS IN BLOOD OTHER PUBLICATIONS R RIN Y 0 E Chem. Abstr. 70, 10920ln (1969) [75] Inventor: Chandra Kant Parekh, North Brun- I Primary Examiner-Morris O. Wolk [73] Assignee: E. R. Squibb & Sons, Inc., New Assistant E ese York, NY. Att0rney-Lawrence S. Levinson et al.

[22] Filled: June 28, 1971 ABSTRACT [211 A No: 157,755 A qualitative and quantitative determination of procainamide blood levels may be obtained by contacting a sample of urine or denatured blood with [52] US. Cl. ..23/230 B, 124/? dimethylcinnamaldehyde in the presence of an acid [51] Int. Cl. ..G01n 33/16 58] and comparing the resulting characteristic color with a Field of Search ..23/23O B; 424/7 reference standard.

6 Claims, No Drawings METHOD FOR DETERMINING PROCAINAMIDE LEVELS IN BLOOD OR URINE BACKGROUND OF THE INVENTION Procainamide is employed medicinally as a cardiac depressant in ventricula andatrial arrhythmias. For such applications it is desirable andv often necessary to determine blood levels of procainamide. Present methods for this determination are time consuming, expensive and require skilled personnel.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a simple, rapid, reliable and inexpensive method for determining procainamide levels ina particular patient. Another object is to provide a method wherein a cardiologist can obtain an immediate and accurate determination of a patients procainamide levels. Another object is to provide a method which can be performed reliably by unskilled personnel. These and other objects of the present invention will be apparent from the following description.

DETAILED DESCRIPTION It has now been found that the reaction of procainamide present in urine or denatured blood with 4- dimethylcinnamaldehyde in the presence of an acid produces a characteristic color ranging from light pink to rose depending upon the amount of procainamide present in the sample. The method of the present invention may be carried out by adding a drop of urine or denatured blood to a small quantity of 4-dimethylcinnamaldehyde and comparing the resulting color with a predetermined standard. The blood may be denatured by contacting an approximately '.l N solution of hydrochloric acid or an equivalent amount of another acid, or by contacting an acidic ion exchange resin. Examples of acids which may be used in addition to hydrochloric are the following: acetic, trichloroacetic, sulfamic, nitric, sulfuric or sulfosalicylic. As examples of acidic ion exchange resins there may be mentioned sulfonated styrene-divinylbenzene copolymers such as Amberlite IR120, Amberlite lR-200, Dowex 50, Dowex 50W, Dowex MPC-l, Duolite C-20, Duolite C-25, Ionac C-240 or Ionac C-250, and resins prepared by crosslinking an unsaturated carboxylic acid such as acrylic, methacrylic or maleic with a crosslinking agent such as divinylbenzene or ethylene dimethacrylate such as Amberlite lRC-SO, Amberlite [RC-84, Duolite CS-lOl, or lonac 0-270. The ion exchange resin and the 4-dimethylcinnamaldehyde may be employed in separate layers.

The blood may be denatured prior to contacting the 4-dimethylcinnamaldehyde or by contacting simultanev ously the acid and 4-dimethylcinnamaldehyde.

The amount of 4-dimethylcinnamaldehyde employed per drop of blood or urine is in the range of from about 5 mg to about mg. Greater amounts of the aldehyde may be used but are uneconomical. The quantity of acid employed per drop of blood is that quantity sufficient to denature the proteins present in the blood. Typically, the amount of acid will be from 5-10 drops of 0.1 N HCl or its equivalent, for example, I drop (approximating l minim) of 30 percent trichloroacetic acid. Antioxidants may be employed if desired to stabilpercent ize the aldehyde. Examples of suitable antioxidants are BHT, vitamin E, tocopherols, and the like.

By previous experiment it has been found that differing levels of procainamide in urine or denatured blood give the following characteristic color when reacted with 4-dimethylcinnamaldehyde:

Procainamide levels Color 2 pg light pink 5 pg pink 7 pg light rose 10 g rose The following examples illustrate the present invention without, however, limiting the same thereto.

EXAMPLE 1 EXAMPLE 2 The procedure of Example 1 is repeated except that 15 mg of 4-dimethylcinnamaldehyde are placed in the tube and 2 drops (each approximating l minim) of 30 trichloroacetic acid is substituted for hydrochloric acid. A drop of blood approximating l minim and containing 5 pg of procainamide is placed on the filter paper. When the clear filtrate passes through the filter paper and contacts the4-dimethylcinnamaldehyde, a characteristic pink color is produced.

EXAMPLE 3 EXAMPLE 4 The procedure of Example 2 is repeated except that 5 drops (each approximating l minim) of acetic acid are substituted for the trichloroacetic acid and 5 mg of 4-dimethylcinnamaldehyde are placed in the bottom of the tube. A drop of blood approximating l minim and containing l0 pg of procainamide is added to the filter paper. When the clear filtrate contacts the 4-dimethylcinnamaldehyde,

a characteristic rose color is produced.

EXAMPLE 5 About 5 mg of 4-dimethylcinnamaldehyde are added to a test tube and then about 5 mg of a sulfonated styrene divinylbenzene copolymer (Amberlite IR-l20) are added. A drop (approximating l minim) of blood containing 5 pg of procainamide is added and there is produced acharacteristic pink color.

EXAMPLE6 The procedure of Example is repeated except that the acidic ion exchange resin and the 4-dimethylcinnamaldehyde are thoroughly mixed before being added to the test tube. When the drop (approximating l minim) of blood is added, the characteristic pink color is produced.

EXAMPLE 7 EXAMPLE 8 The procedure of Example 5 is repeated except that a drop (approximating l minim) of urine containing 2 ug of procainamide is substituted for the blood. In this case the characteristic light pink color is obtained.

What is claimed is:

1. A method for determining procainamide blood levels which comprises contacting urine or denatured blood with 4-dimethylcinnamaldehyde in the presence of an acid and comparing the resulting color with a predetermined standard.

2. A method according to claim 1 wherein the acid is acetic, trichloroacetic, sulfamic, nitric, sulfuric or sulfosalicylic.

3. A method according to claim 1 wherein the blood is denatured by contacting an acidic medium.

4. A method according to claim 3 wherein the acidic medium is an acidic ion exchange resin.

5. A method according to claim 4 wherein the acidic ion exchange resin and the 4-dimethylcinnamaldehyde are in intimate admixture in a single layer.

6. A method according to claim 4 wherein the acidic ion exchange resin and the 4-dimethylcinnamaldehyde are in separate layers. 

1. A method for determining procainamide blood levels which comprises contacting urine or denatured blood with 4-dimethylcinnamaldehyde in the presence of an acid and cOmparing the resulting color with a predetermined standard.
 2. A method according to claim 1 wherein the acid is acetic, trichloroacetic, sulfamic, nitric, sulfuric or sulfosalicylic.
 3. A method according to claim 1 wherein the blood is denatured by contacting an acidic medium.
 4. A method according to claim 3 wherein the acidic medium is an acidic ion exchange resin.
 5. A method according to claim 4 wherein the acidic ion exchange resin and the 4-dimethylcinnamaldehyde are in intimate admixture in a single layer. 